It is known that copper conductors in the various designs can be injected into the housing plastics material as an insertion part (insert technique) or laid on it. This is, however, expensive since complex insertion parts have to be used in the shaping process. Similar to the conventional production of printed circuit boards are methods in which the inside of the housing is first electroplated completely. Coating is then carried out with a photoresist and the conductor pattern is structured by various exposure techniques (masks, laser), with subsequent development (etching). Two-component injection-molding methods (cf. European Patent Specifications 564 019-A2, 323 685-A, 256 428-A), in which the conductor pattern is first injection molded by means of a metallizable plastics material are advantageous. However, the plastics material must then be pretreated by various expensive methods (for example, Pd-nucleated). In the third step, the spaces between the conductor tracks are filled in. Copper or nickel is then deposited electrolessly on the surface of the pretreated material. Additional metal layers can be applied to these layers in further steps.
These methods require a very good adhesion of the metal to the plastics material. To increase the adhesion, a complicated, expensive and environmentally polluting pretreatment is required. In addition, the methods comprise a number of different individual steps which can be automated only with difficulty.